Here are some of Areneus spiders at the same magnification. As using flash on the hotshoe prevents use of the VF-2 high resolution viewfinder, I was left using the rather poor rear live view screen. Thus focusing was very much hit and miss.

Images uncropped.

Harold_________________My images are a medium for sharing some of my experiences: they are not me.

Last edited by Harold Gough on Thu Oct 18, 2012 10:16 am; edited 1 time in total

This was shot with the same setup as yesterday (zoom at 70mm), except:

1) The flash was fitted with a dedicated diffuser.

2) The flash was mounted on a tripod clamp ring (designed for clamping lenses to tripods) so that its front was about level with the lens mount (nearest subject) and angled downwards at 45 degrees or thereabouts.

3) A hotshoe extension lead with an OM TTL cord connected to the back of a T20 hotshoe, attached, in turn, to the tripod thread of a tripod-mount flash hotshoe accessory.

4) The proximity allowed the ISO to be dropped to 200 from the 800 used up to this point.

5) The rather wobbley grip and unreliable aim of the gun on the camera hotshoe, and its metering ability, were thus regularised.

FOV 10mm wide. Hand-held, manual flash 1/160 sec.

As I hadn't got the subject quite in the same plain as the sensor, I have cropped off the top of the image:

A reshoot (below) shows the aperture to have been f8, not f11 as I believed.

Harold_________________My images are a medium for sharing some of my experiences: they are not me.

I have taken further shots of the stamens. This time I have zoomed the lens out to 28mm, giving a FOV 3mm wide. I retained the f11 and increased ISO to 800.

Partly because of the inherent difficulty of hand-held photography at this magnification and partly because of windy conditions, I detached the flower and placed it on a conservatory bench. Thus I had considerable, steadying support for camera and subject and no wind to contend with.

These are uncropped:

It is my conclusion that working with this 3mm FOV is impractical for most field use and it would be better to work with a shorter extension, and lower ISO, except inexceptional circumstances.

Harold_________________My images are a medium for sharing some of my experiences: they are not me.

Last edited by Harold Gough on Sat Oct 20, 2012 9:23 am; edited 1 time in total

There are two red lines on the aperture ring and I believe that the f11 was, in fact half a stop larger. This post uses f11.

The diffuser for the T32 flash is like a rectangular box, the open end sliding onto the front glass of the flash. Made of white plastic, it protrudes forward some 25 mm/1". This means that light emerges from not oly the front panel but all four side ones. Wonderful for studio work but a waste of light for macro.

So I wrapped some cooking foil around it, as a kind of snoot, extending forward by about 10mm beyond the front of the diffuser to further direct the light. This was such a saving of light that, with the previous flash setting, even at ISO 100, I was getting overexposure. So I set the gun to manual, half power (GN16). This gave spot-on exposure.

Today I added a second, smaller flash gun via a second lens tripod clamp. This was a T20, connected to the other flash and the camera via an OM 3-way TTL connecter and cord. The diffuser was four layers or white packing materia, which feels like tough rubber foam.

Both flash guns were on manual, the T32 on half power.

An initial test showed that the combined light intensity from this flash setup was correct for f11 at ISO 100 but it was found that correct exposure was given by f16. Most (possibly all) shots were at f16.

Here is a springtail Tomocerus sp at f16, FOV 10mm wide. I didn't quite get the dorsal surface sharp but this shows the potential. This has been heavily processed so the image quality is not the main interest this time. Those dark, plate-like structures are striated scales.

It is unusual to find one posing like this and remaining still for several shots. Maybe it will return to the same place.

Harold_________________My images are a medium for sharing some of my experiences: they are not me.

I recently came across an f4, constant aperture, oversion of this lens. I considered it briefly and then checked hiow my 3.5-4.5 performed on this setup.

Within the limits of the camera's display, the brightness at 28mm is 50% greater than at 70mm, both at closest focusing. Thus the image is brighter at the higher magnifcation, where it is more critical for focusing and where a smaller aperture may be needed for DOF.

Harold_________________My images are a medium for sharing some of my experiences: they are not me.

I recently came across an f4, constant aperture, oversion of this lens. I considered it briefly and then checked hiow my 3.5-4.5 performed on this setup.

Within the limits of the camera's display, the brightness at 28mm is 50% greater than at 70mm, both at closest focusing. Thus the image is brighter at the higher magnifcation, where it is more critical for focusing and where a smaller aperture may be needed for DOF.